1. Field of the Invention
This invention relates to a multi-tip semiconductor laser and particularly relates to a multi-tip semiconductor laser for emitting a visible light.
2. Description of the Prior Art
A multi-tip semiconductor laser for emitting a short wavelength laser light is known which comprises an active layer and a cathode layer having a multi-tip field emission array, the cathode layer being so arranged that multi-tip field emission array confronts the active layer. The active layer is excited to emit laser light by electron beams radiated from respective tips of the multi-tip filed emission array by electrostatic fields applied therebetween. Such semiconductor laser is disclosed in Japanese patent application provisional publication No. 2-188980. FIG. 5 is a cross-sectional view of this prior art multi-tip semiconductor laser.
In FIG. 5, numeral 101 is a GaAs substrate, numeral 102 is a ZnS clad layer, numeral 103 is a Zn S active layer, numeral 104 is SiO.sub.2 film, numeral 105 is SiO.sub.2 film, numeral 106 is a field emission tip, numeral 107 is a Si substrate, numeral 108 is a vacuum space, and numeral 109 is a Mo electrode film.
In the prior art multi-tip semiconductor laser, the active layer 103 comprises II-VI group compound semiconductor and it emits a blue laser light by a slab type light waveguide structure.
However, there is a problem that oscillation wavelength is limited by use of II-VI group compound semiconductor for the active layer, that is, it cannot provide a laser light of other wavelength. Further, there is a problem that it is difficult for this slab type light waveguide structure to provide only single transverse mode oscillation.